Electrical coil



Sept. 15, 1925. 1,553,983

.w. L. CASPER ELECTRICAL COIL F'iie'd Dec. 26. 1919 lfiV/W'OK' M///amL.Ca pen Arty Patented Sept. 15, 1925.

UNITED STATES 1,553,983 PATENT OFFICE.

WILLIAM L. CASPER, OF BROOKLYN, NEW YORK, ASSIGNOR T WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A. CORPORATION OF NEW YORK.

ELECTRICAL COIL.

Application filed December 26, 1919. Serial No. 347,391. i

To all whom it may concern:

Be it known that I, WILLIAM L. CASPER, a citizen of theUnited States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Electrical Coils, of which the following is a full, clear, concise, and exact description.

This invention relates generally to elec- 0 trical coils and more particularly to transformer and retardation coils.

The object of the invention is to provide a compact and convenient form for combining a mutually noninterfering retardation coil and transformer in the-same physical structure. a

This is accomplished in accordance with the invention in its preferred form by the use of a magnetic core having the form of an enclosed H. Primary and secondary transformer windings are placed on the outer legs of the core and these windings are balanced so that the magnetic effect in each leg is equal. The middle leg of the 5 core connects points of equal magnetic potential and is unaffected by the flux variations in the. other two legs. A retardation coil placed on this intermediate leg is therefore unaffected by the transformer ourrents.

The invention may be more completely understood by reference to the drawing which illustrates the invention in its preferred embodiment. The core structure is shown in side elevation and the coil windings to be placed thereon, are shown diagrammatically.

Referring to the drawing which illus trates the invention in its preferred form, a T-shaped section 1, and a U-shaped section 2, are fitted together at the faces 3, 1 and 5, to form a closed magnetic structure having the legs 6, 7 and 8.

On the leg 6 of the section 1, is wound a retardation coil 9 of any desired number of turns.

Two coils 10 and, 12 are wound on the legs 7 and 8 respectively, and are connected together to form the transformer primary winding. Coils 10 and 12 are composed of the same number of turns and are otherwise similar in order to produce equal inductive eifects.

Coils 11 and 13 are Wound on the legs 7 and 8 respectively and are connected together to form the transformer secondary winding. They are composed of the same number of turns and are otherwise similar in order that equal inductive effects may be produced'in them.

The transformer primary and secondary, and the retardation coil are adapted to be connected in separate electrical circuits. For example, the primary winding 10, 12 and the secondary winding 11, 13 may be employed for coupling a vacuum tube repeater to an outgoing line, the primary winding being connected in circuit wit-h the output electrodes ofthe tube, while the secondary winding is connected in circuit with the outgoing line. The retard coil 9 could be employed, for example, to prevent the alternating currents in the output circuit of such a .repeater from passing through the battery employed as the output circuit source of voltage. This may be safely done because there is no inductive coupling between winding 9 and the primary and secondary windings 10, 12 and 11, 13. The construction shown ure therefore enables the same magnetic structure to be employed both for the retard coil as well as the transformer without objectionable inductive effects therebetween.

Flux in leg 6, due to current in coil 9, divides and takes paths in opposite directions through the legs 7 and 8, and the inductive effects in coils 10 and 11 are neutralized by the inductive effects in coils 12 and 13 respectively.

Flux in legs 7 and 8 produced by current in elther coils 10 and 12 or coils 11 and 13, does not pass through leg 6 since leg 6 connects points of equal magnetic potential. Thierefore no inductive eifect is produced in coi 9.

WVhen operating simultaneously the decrease in flux in either leg 7 or 8, due to the flux of leg 6, is ofiset by a corresponding increase in flux in the other leg so that the total 'efiect due to leg 6 on the other two legs is zero.

What is claimed is:

1. A combined structure for a transformer and a retardation coil consisting of a three legged closed magnetic core, transformer windings wound on two only of said legs and a retardation coil Winding wound on the other of said legs.

in the fig-.

- adjacent legs;

2. A combinedastructure for a mutually noninterfering transformer and retardation coil, said structure consisting of a closed magnetic core having two non-adjacent legs and an intermediate leg; a primary transformer winding Wound on the said nonadjacent legs; a secondary winding simi larly wound on the said non-adjacent'legs;

and a retardation coil winding wound on said intermediate leg.

3. A combined structure for a mutually non-inductive transformer and retardation coil, said structure consisting of a closed magnetic. core having two non-adjacent legs and an intermediate leg; equal primary transformer windings wound on said nonequal secondary windings wound on said non-adjacentlegs; and a retardation coil winding wound on said intermediate 1e". v

4. A combined structure for a mutually non-inductive transformer and a retardation coil, said structure consisting of a magnet core composed of an enclosed H section; equal primary windings wound on. the outer legs of sai core; equal secondary windings also wound on the outer legs of said core; and a retardation coil Wound on the middle leg of the said core.

5. An inductance device comprising a substantially closed two-mesh magnetic structure having a common portion and a portion individual to each mesh, primary and secondary transformer windings WOUllCl on said structure, a retard winding on said structure, said windings being arranged on said structure such that magnetic flux in said structure produced by current 111 sald vretard winding does not produce a current in said primary and secondary windings.

In witness whereof, I hereunto subscribe my name this 22nd day-of Deceniber A.- D.,

WILLIAM L. CASPER. 

